codecombat/server/commons/LockManager.coffee
2014-07-16 12:12:44 -07:00

30 lines
1.1 KiB
CoffeeScript

config = require '../../server_config'
redis = require 'redis'
class LockManager
constructor: ->
unless config.isProduction or config.redis.host isnt "localhost"
throw "You shouldn't be instantiating distributed locks unless in production."
@redisClient = redis.createClient config.redis.port, config.redis.host
@lockValues = {}
@unlockScript = "if redis.call(\"get\",KEYS[1]) == ARGV[1] then return redis.call(\"del\",KEYS[1]) else return 0 end"
setLock: (lockName, timeoutMs, cb) =>
randomNumber = Math.floor(Math.random() * 1000000000)
@redisClient.set [lockName,randomNumber, "NX", "PX", timeoutMs], (err, res) =>
if err? then return cb err, null
if res is "OK"
@lockValues[lockName] = randomNumber
return cb null, "Lock set!"
unless res
return cb "Lock already set!", null
releaseLock: (lockName, cb) =>
@redisClient.eval [@unlockScript, 1, lockName, @lockValues[lockName]], (err, res) ->
if err? then return cb err, null
if res
cb null, "The lock was released!"
else
cb "The lock was not released.", null
module.exports = new LockManager()